Elongate medical devices are used to access interior portions of patients' bodies. Oftentimes, the pathway to the site of interest within the body can be tortuous, small in size, obstructive, significantly angulated, or a combination of these factors. The medical devices, including catheter, often have elongate shafts that aid the tracking or accessing of the site or sites of interest. Medical device shafts are commonly designed with the purpose of achieving the desired combination of flexibility, profile, trackability, pushability, tensile strength, lubricity. However, the shafts oftentimes have other requirements, the fulfillment of which can compromise the previously described attributes, such as the need to place other medical devices within them, to transfer fluids (injection and aspiration) and to envelop of otherwise carry elongate operative components (electrical wires, optical fibers, etc.).